Methane

Methane

From Coal To Methane with Microbes

Ciris Energy

Anaerobic Digester -Bellingham Technical College








Michigan State Anaerobic Bio Digester





5 Categories of Digesters

1. CSTR (Complete Stirred Tank Reactor
   1. Vertical steel tank- small footprint
   2. Found in Europe and waste water facilities
   3. Provide very consistent environment for bacteria - therefore they are easy to control except for duration of process

2. Plug - Flow (First in - First out) - works like a tube of toothpaste

• Vertical tank design
• more difficult to completely mix

3. Pack Bed Biofilm Reactor

• Packing provides surface area for bacteria
• Packing can be engineered or shredded plastics or rubber
• provides higher population of bacteria
• clogs easy. Especially if wastes are high in fiber

4. Covered Lagoon

• No heat
• No Mix
• Must be in warm regions - below the 40th Parallel
• cheapest

5. UASB (Up Flow Anaerobic Sludge Bed)

• Sludge comes up from bottom
• Most industrial waste-water systems use this
• Bacteria cling together (snowball affect) forming beads
• Beads (pellets make up the bed
• enormous bacteria population

How Bio Gas Plant Operates